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Background Dislocation is a major complication in revision total hip arthroplasties. This study aimed to evaluate the dislocation rate, complications, and functional scores of revision total hip arthroplasty performed through the direct anterior approach. Methods Between January 2014 and March 2020, 84 patients undergoing revision total hip arthroplasty were retrospectively reviewed. All operations were performed through the direct anterior approach. At the final follow-up, incidences of dislocation, reoperation, acute deep infections, periprosthetic fractures and psoas impingement were assessed. The median postoperative Oxford Hip Score was also calculated. Results At revision surgery, the mean age was 66 ± 12 years (range, 28–91). During an average follow-up of 4.2 ± 1.2 years, reoperation rate for major complications in the non-infected revisions was 15% (n = 11), including five acute deep infections (7%), four periprosthetic fractures (5%), one dislocation and one psoas impingement (1%). The median postoperative Oxford Hip Score was 39 (interquartile range = 14). Conclusion In our series, revision total hip arthroplasty through direct anterior approach was associated with a very low dislocation rate, acceptable complication rates and good functional results. Our results suggest that this procedure is safe and reliable. Trial registration Ethical approval for this study was obtained, before enrollment of the first participant, by CUB Erasme's research ethics committee (P2020/323) and C.H.U Ambroise Paré's research ethics committee.

A non-comparative multi-centre and international pilot study have been carried on Y-STRUT® (Hyprevention, France), an implantable medical device meant to reinforce the hip to reduce the risk of a contralateral hip fracture. Objectives of the study were to determine the feasibility and tolerance of the procedure. Methods Patients older than 60 years were recruited when presenting at the emergency departments with a low-energy pertrochanteric fracture on one side and with a fracture risk assessed for the contralateral side with BMD, T-Score or other bone quality evaluation tool, FRAX index, or fall risk assessment. Pain and functional ability were assessed at the different follow-up visits using VAS, WOMAC and OHS-12 scores. Results Twelve patients were included and reached a one-year follow-up. Mean age was 82 years old (65 – 91). The average hospital stay was 13 days (3 – 29). The prophylactic surgery did not delay the hospital discharge for any patient. The procedure did not lead to unresolvable serious adverse events. At 3 weeks, all patients were able to walk 6 meters, half of them in less of 30 seconds. Minimal pain was reported all along the follow-up visits, except at 3 years when one patient presented high pain in both hips. WOMAC and OHS-12 scores showed a moderate to mild hip impairment. Conclusion The good short and medium-term outcomes of this pilot study demonstrate the feasibility and the tolerability of the device. Further studies should focus on the efficacy of this immediate and lasting bone reinforcement technique.

Background Degenerative or traumatic tendon injuries are extremely common but often heal poorly, not restoring the normal function of the injured tissues. Gene transfer could improve the repair process, by permitting local production of therapeutic substances, e.g. growth factors. Methods and results Injection of a plasmid carrying the lacZ marker gene was performed into the Achilles tendons of rat and mouse, and the patellar tendons of rabbit. At 48 h, transduced cells were found in the injected zones of the tendons but represented a minority of the tendon cells. A kinetics study in rats permitted observation of a gradual decrease with time in the β-gal-expressing cell number; at day 42 no more gene expression was detected. Noteworthy, no inflammatory reaction was observed. We then investigated whether electrotransfer could improve gene transfer efficacy in rat tendon by delivering in situ electric pulses after DNA injection. Gene transfer was improved at best by ≈50% under certain electrical conditions (200 V for 10 ms or 1200 V for 100 µs). Finally, multiple injections of plasmid permitted an increase in the number of transduced cells by ≈400%. Conclusions In situ injection of naked DNA into tendons is a very simple technique that permits delivery of genes with a duration of expression sufficient for clinical application aimed at modulating healing or restoration of a degenerative tendon. Despite a low transfer efficiency, this method should be compatible with clinical applications aimed at delivering therapeutic substances acting at low concentration. Copyright © 2003 John Wiley & Sons, Ltd.

Nonunion fractures can cause severe dysfunction and are often difficult to treat mainly due to a poor understanding of their physiopathology. Although many aspects of impaired fracture healing have been extensively studied, little is known about the cellular and molecular mechanisms leading to atrophic nonunion. Therefore, the aim of the present study was to assess the pools and biological functions of bone marrow-derived mesenchymal stem cells (hMSCs) and circulating endothelial progenitor cells (EPCs) in atrophic nonunion patients compared to healthy subjects, and the systemic levels of growth factors involved in the recruitment, proliferation and differentiation of these cells. In nonunions, the pool of hMSCs was decreased and their proliferation delayed. However, once committed, hMSCs from nonunions were able to proliferate, differentiate into osteoblastic cells and mineralize in vitro as efficiently as hMSCs from healthy subjects. In parallel, we found altered serum levels of chemokines and growth factors involved in the chemotaxis and proliferation of hMSCs such as leptin, interleukin-6 (IL-6) and its soluble receptor, platelet-derived growth factor-BB (PDGF-BB), stem cell factor (SCF) and insulin-like growth factor-1 (IGF-1). Moreover, we showed that the number of EPCs and their regulating growth factors were not affected in nonunion patients. If nonunion is generally attributed to a vascular defect, our results also support a role for a systemic mesenchymal and osteogenic cell pool defect that might be related to alterations in systemic levels of factors implicated in their chemotaxis and proliferation.

Degenerative or traumatic tendon injuries are extremely common but often heal poorly, not restoring the normal function of the injured tissues. Gene transfer could improve the repair process, by permitting local production of therapeutic substances, e.g. growth factors.Injection of a plasmid carrying the lacZ marker gene was performed into the Achilles tendons of rat and mouse, and the patellar tendons of rabbit. At 48 h, transduced cells were found in the injected zones of the tendons but represented a minority of the tendon cells. A kinetics study in rats permitted observation of a gradual decrease with time in the beta-gal-expressing cell number; at day 42 no more gene expression was detected. Noteworthy, no inflammatory reaction was observed. We then investigated whether electrotransfer could improve gene transfer efficacy in rat tendon by delivering in situ electric pulses after DNA injection. Gene transfer was improved at best by approximately 50% under certain electrical conditions (200 V for 10 ms or 1200 V for 100 micro s). Finally, multiple injections of plasmid permitted an increase in the number of transduced cells by approximately 400%.In situ injection of naked DNA into tendons is a very simple technique that permits delivery of genes with a duration of expression sufficient for clinical application aimed at modulating healing or restoration of a degenerative tendon. Despite a low transfer efficiency, this method should be compatible with clinical applications aimed at delivering therapeutic substances acting at low concentration.

A 22-year-old African male with known sickle cell anaemia was referred by a Congolese medical centre with a request to improve his poor physical condition. He was unable to walk, stand or sit because his large joints and his spine were either ankylosed or very rigid. Radiographs showed joint fusion from the third to the fifth cervical vertebrae, of both hips, of the left knee, and a bilateral osteonecrosis of the humeral head. There was no scintigraphic evidence for an active osteomyelitis (99mTc-MDP (methyldiphosphonate) bone scan, Tc monoclonal antigranulocyte scan and 99mTc sulphur colloid scan). To improve his mobility the right femoral head was resected in June 1997; 14 days later the left femoral head was resected. Four months after the resection of the right hip, a right uncemented total hip prosthesis was implanted on this side. One month later the same type of hip arthroplasty was performed on the left side. During the postoperative rehabilitation period the patient regained autonomy. We have found no previous reports of such severe and multiple joint complications in a single patient suffering from sickle cell anaemia.